A tire anti-slip device of the prior art is discussed in Japanese Laid-open Patent Publication No. 2001-71728, in which the tire anti-slip device includes a net-type tire anti-slip body 601, connectors 602a and 602b configured to connect both ends of the tire anti-slip body 601 to each other in the inner side position of the tire, connectors 603a and 603b configured to connect both ends of the anti-slip body 601 to each other in the outer side position of the tire as illustrated in FIG. 43. In the anti-slip device described above, a clamp lock mechanism 604 is provided in the anti-slip body 601 in the outer side position of the tire in order to reduce a distance between both ends and tightly fit the anti-slip device to the tire.
However, in the aforementioned tire anti-slip device of the prior art, when it is mounted to the tire, the connectors 602a, 602b, 603a, and 603b used to connect both ends of the tire anti-slip body are provided in both the inner and outer side positions of the tire. In particular, it is difficult to perform a work for connecting the connectors 602a and 602b in the inner side position of the tire, where an arm insertion gap is small, and dirt such as mud is easily adhered. In addition, this work may make user's clothes dirty disadvantageously.
In order to address such problems, a tire anti-slip device is discussed in Japanese Laid-open Patent Publication No. 04-238704, in which, as illustrated in FIG. 44, the tire anti-slip device has an anti-slip body 701 disposed to make contact with a tire along an outer circumference of the tire, holding members 702 provided in inner end portions of the anti-slip body 701 in the tire width direction with a predetermined interval, latching members 703 provided in outer end portions of the anti-slip body 701 in the tire width direction with a predetermined interval, a strap-like tensioning member 704 configured to connect the holding members 702 to each other with a variable interval and guided to a lateral side of the latching member through a hollow portion 705 provided inside the anti-slip body in the tire width direction, and an elastic member 706 such as rubber or a spring provided in an end portion of the tensioning member 704, so that the holding members 702 positioned in the inner side of the tire are fastened by drawing both ends of the tensioning member 704 from the outer side of the tire.
Since a work for mounting the tire anti-slip device to the inner side of the tire can be performed in the outer side of the tire, it is possible to simplify the mounting work and reduce the time required to mount the tire anti-slip device. In addition, since hooking in the inner side of the tire is not necessary, it is possible to prevent user's clothes from being dirty. Furthermore, since the inner side of the tire is fastened using the strap-like tensioning member 704 having no elasticity, it is possible to improve an abutting force to the outer circumference of the tire. Moreover, it is possible to prevent lost components through integration of components.
However, in the technique discussed in Japanese Laid-open Patent Publication No. 04-238704, a position for attracting one end portion and the other end portion of the anti-slip body 701 in the longitudinal direction by drawing both ends of the tensioning member 704 is placed only in a part of the holding members 702 disposed in the inner side of the tire. Therefore, when one end portion 701a and the other end portion 701b of the anti-slip body 701 are attracted to each other by drawing both ends of the tensioning member 704, the anti-slip body 701 is attracted toward the inner side of the tire. Therefore, it is necessary to reduce a distance between the one end portion 701a and the other end portion 702b in the outer side of the tire by drawing both ends of the tensioning member 704, hooking, to each latching member 703, a part of the tensioning member 704 extracted to the outer side of the tire, hooking an elastic member 706 such as rubber or a spring provided in the end portion to an arbitrary position of the latching member 703, and moving the anti-slip body 701, that has been attracted to the inner side of the tire, to the outer side of the tire.
Since the hollow portion 705 perforated in the tire width direction and used to extract the tensioning member 704 to the lateral side of the latching member 703 is formed far from the longitudinal positions of the one end portion 701a and the other end portion 701b of the anti-slip body 701, the attracting force between the one end portion 701a and the other end portion 701b of the anti-slip body 701 in the longitudinal direction may be weakened due to a frictional resistance between the holding members 702 and the tensioning member 704 of the anti-slip body 701 provided in the inner end portion of the tire in the tire width direction with a predetermined interval when both ends of the tensioning member 704 are drawn.
In another technique of the prior art discussed in Japanese Laid-open Patent Publication No. 04-125906, a tire anti-slip device is configured such that both ends of a rim 802 penetrating through edges (in the tire inner side) of a plurality of anti-slip pieces 801 are guided by a guide piece 804 as extracting portions 803 from a rear side to a front side of the tire as illustrated in FIG. 45. Each of the extracting portions 803 in both ends of the rim 802 is guided from the left and right directions to a generally T-shaped portion formed in one end of the guide piece 804 (in the inner side of the tire), passes through the guide piece 804, and is guided to the outer side of the tire through a roller 805. In this technique of the prior art, when the extracting portions 803 in both ends of the rim 802 passing through the guide piece 804 are guided to the front side of the tire, the frictional resistance with the rim 802 can be reduced using the roller 805. However, a portion of the generally T-shaped portion formed in one end of the guide piece 804 (in the inner side of the tire) to receive the rim 802 is a horizontal hole formed in an end portion of the inner space of the guide piece 804. Therefore, this structure is not suitable for sufficiently reducing the frictional resistance. Furthermore, this tire anti-slip device does not have a structure corresponding to the one end portion and the other end portion of the anti-slip body in the longitudinal direction, and it is necessary to tension each of a pair of left and right extracting portions 803a and 803b oppositely to the guide piece 804 when the rim 802 is tightened by drawing the extracting portions 803 in both ends of the rim 802.